One particle interchain hopping in coupled Hubbard chains

TL;DR

This paper investigates how interchain hopping in coupled Hubbard chains is affected by electron interactions, revealing that while the coherent band splitting is reduced, incoherent spectral features remain largely unaffected, indicating possible incoherent interchain hopping.

Contribution

It demonstrates that repulsive interactions reduce the coherent interchain hopping in coupled Hubbard chains, while incoherent spectral features are less impacted, suggesting new mechanisms for interchain transport.

Findings

Fermi level splitting is reduced but not suppressed by interactions.

Incoherent spectral function parts are less affected by interchain coupling.

Incoherent hopping may occur at intermediate interaction strengths.

Abstract

Interchain hopping in systems of coupled chains of correlated electrons is investigated by exact diagonalizations and Quantum-Monte-Carlo methods. For two weakly coupled Hubbard chains at commensurate densities (e.g. n=1/3) the splitting at the Fermi level between bonding and antibonding bands is strongly reduced (but not suppressed) by repulsive interactions extending to a few lattice spacings. The magnitude of this reduction is directly connected to the exponent $\alpha$ of the 1D Luttinger liquid. However, we show that the incoherent part of the single particle spectral function is much less affected by the interchain coupling. This suggests that incoherent interchain hopping could occur for intermediate $\alpha$ values.